1. Field of the Invention
The present invention relates to a heat dissipating fan, and more particularly to a heat dissipating fan that can be assembled easily, precisely and securely.
2. Description of the Related Art
Referring to FIG. 1, to assemble the fan wheel 11 of the conventional heat dissipating fan 1, the shaft 12 of the motor is inserted into the collar 112 disposed at center of the inner side of the hub 111.
The process of assembling the fan wheel 11 to the shaft 12 includes, first, preparing a fan mold (not shown) to vertically receive the shaft 12 in the space reserved for the collar 112. Next, a molten plastic is injected into the mold, and then it is cooled down to form the hub 111 with the collar 112 before the mold is removed. In this way, the shaft 12 is joined to the color 112 of the hub 111.
However, the shortcoming of the preceding process for forming the fan wheel 11 is in that when the molten plastic material is injected in the injection molding process, the shaft 12 is pushed with the injected molten plastic material easily to result in the phenomena of misalignment. Thus, the axial line of the hub 111 is unable to coincide with the axis of the shaft 12, and the fan wheel 11 is incapable of rotating smoothly to deteriorate the heat dissipation effect. Correction of the misaligned shaft 12 would incur extra time and labor due to complexity of the correction process and would substantially increase the overall assembling cost.
FIG. 2 illustrates another conventional process of assembling the shaft 32 of the fan motor and to the fan wheel 31 of the heat dissipating fan 3. First, the fan wheel 31 is formed, and then the shaft 32 of the motor is inserted into the collar 312 with tight fit or glue fastening to complete the assembly.
However, for implementing the process of inserting and adhering the shaft 32 and the collar 312 have to have their dimensions thereof with high precision. Besides, during the assembly process, an end of the shaft 32 must enter the hub 311 and join with the collar 312. However, the joint of the shaft 12 at the collar needs a very strict precision. Otherwise, an unfavorable joint will be created even if there is a little dimension error. Therefore, this conventional process is much more complicated.